A method to one-pot synthesize solid fluorescent materials by coating carbon dots via the crystallization of phthalic acid precursor as matrix is reported. The crystalline CDs， emitting blue and green fluorescence respec-tively， are synthesized by changing the solvent in microwave method. After detailed structural and spectral character-izations， it is found that a crystalline matrix is grown around the CDs by the phthalic acid precursor when the CDs is formed， and the dispersion effect of the matrix on the CDs effectively blocked the aggregation of the CDs， thus preventing the occurrence of fluorescence quenching of the CDs. Furthermore， the change of crystalline matrix structure in G-CDs leads to the increase of pyridine nitrogenous groups at the interface between core and matrix in the CDs， resulting in a change of fluorescent color of the CDs with different crystalline structures. The resultant crystalline CDs are also used to fabricate white-light emitting diode devices (WLED) in view of its excellent luminescence perfor-mance， which achieves a warm-white light with the correlated color temperature (CCT) of 4 061 K， color rendering index (CRI) of 88. 4 at the chromaticity coordinates of (0. 37， 0. 36) using B-CDs combined with the commercial phosphors and another warm-white light with the CCT of 4 478 K， CRI of 85 at the chromaticity coordinates of (0. 36， 0. 34) using G-CDs combined with the commercial phosphors. The excellent photometric parameters give